Superconductivity induced by oxygen deficiency in Sr-doped LaOFeAs

Abstract

We synthesized Sr-doped $L{a}_{0.85}S{r}_{0.15}OFeAs$ sample with single phase, and systematically studied the effect of oxygen deficiency in the Sr-doped LaOFeAs system. It is found that substitution of Sr for La indeed induces the hole carrier evidenced by positive thermoelectric power (TEP), but no bulk superconductivity is observed. The superconductivity can be realized by annealing the as-grown sample in vacuum to produce the oxygen deficiency. With increasing the oxygen deficiency, the superconducting transition temperature ($T_c$) increases and maximum $T_c$ reaches about 26 K the same as that in La(O,F)FeAs. TEP dramatically changes from positive to negative in the nonsuperconducting as-grown sample to the superconducting samples with oxygen deficiency. While $R_H$ is always negative for all samples (even for Sr-doped as grown sample). It suggests that the $L{a}_{0.85}S{r}_{0.15}{O}_{1-\delta }FeAs$ is still electron-type superconductor.

4 pages, 4 figures

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• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
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• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Superconductivity at 25 K in hole doped $(L{a}_{1-x}S{r}_x)OFeAs$
• Nernst effect of the new iron-based superconductor LaO${}_{1-x}$F${}_x$FeAs

Cited by in corpus (6)

• Effect of Co doping on superconductivity and transport properties in SmFe${}_{1-x}$Co${}_x$AsO
• Superconductivity induced by cobalt doping in iron-based oxyarsenides
• Structural and electronic response upon hole-doping of rare-earth iron oxyarsenides Nd1-xSrxFeAsO (0 < x < 0.2)
• Electronic and lattice dynamical properties of the iron-based superconductors LiFeAs and NaFeAs
• Theoretical investigation of magnetic order in ReOFeAs, Re = Ce, Pr
• Superconductivity in layered iron Selenide induced by cobalt- and sodium-doping